I realize this isn't your opening 13, so I will have to presume you give the reader some substance in the previous chapter. Flashbacks are very rarely a good thing.

Does it flow well? Not really. I'm choking on the description. It interrupts the flow of the action, which is: MC sees girl, MC has emotional reaction, MC says something.

Does it give me a vivid imagery of the MC's thoughts? No. Vivid imagery truly has very little to do with physical descriptions, like "lithe body" and "red hair flowing". Vivid imagery has more to do with the MC's reactions.

You gave us this line: At the mention of her name, Hyldain's mouth worked to say something...
In my opinion, it was the best line in the paragraph. I got a very vivid image of how he was feeling.

Keep in mind the MC is not going to be thinking to himself, "My, she has a lithe body and fine red flowing hair." The MC is going to be thinking things like: "Does she ever think of me? Do I stand a chance with her?"

Does it flow? Not so much. It tends to bounce from Hyldain to his vision and back again too much.

I think the sentence beginning "They had last been together..." needs to be the second sentence, not the sixth. It sets the stage for his memory and segues nicely into the memory itself. It also lets us move into Hyldain's memory and out again at the same time he does.

I think this sentence needs work: "She stood in front of a wide window, sunlight shining through onto her lovely hair and speaking with the King."

It sounds like the sunshine is doing the speaking, not Elle.

I would also re-write the sentence, "She stood in front of a wide window, sunlight shining through onto her lovely hair and speaking with the King." When you interrupt the sentence with "Sunlight shining through onto her lovely hair" it kinda makes the sentence a litle awkward. I would either set it off fromthe main sentence with hyphens or say something along the lines, "With sunlight shining onto her lovely hair, she stood in front of the wide window speaking with the king." And that's still a bit awkward but you get the picture.

I would also think about using an adjective to describe her hair. I would drop it and maybe use it to describe her hair at some point previous to this or if this is the first time she appears use it in some other paragraph.

I would also add "Hyldain now pictured her as best he remembered. She stood in front of a wide window, sunlight shining through onto her lovely hair and speaking with the King, " to the first paragraph as it would describe his memory of Elle.

I like the paragraph you gave to us. It is definitely workable, and I can picture the scene you are giving us to view. I would just play around with the wording so that it flows like water. As for the adjectives, I like sentences to be a little wordy. I tend to stray away from sentences that are choppy and straight to the point. They have their place but too many and I start to doubt the writing ability of the author as far as discription is concerned. In my opinion, an author should paint a masterpiece with his powers of description. It should be like a mini skirt on a woman... short enough to get and keep your attention and long enough to cover all the important parts.

Peace,
Scott

I do see some problems with it as it is written.

1) I see no need to insist on making the reader believe Elle's image is actually before Hyldain at the current time. It lengthens the passage, and it confuses the tenses, mixing now and then. For instance, since your main narrative is in the past simple, I'd expect the phrase: "the last time he'd seen Elle" not the last time he saw Elle. I'd expect "She had stood" not she stood, ect.

2)Attributing physical characteristics is an important element of building fantasy characters and I see no problem repeating these characteristics as does a tale like the Iliad (rosy-fingered dawn, golden-haired Meleager, Iris of the golden wings).

In order for these identifying characteristics to make their impact, only a few should be chosen as repetitive identifiers. Too many details destroy the effect. It seems to me that Elle's long, red hair may be her distinguishing characteristic. Perhaps it would be better to leave out the color of her dress, her eyes, the litheness of her form. Or perhaps certain characteristics are mentioned based on the context. For example, her red hair is evoked when describing her magical abilities, her lithe form when describing her in battle.