Lines 11-12

Lo, in yon brilliant window-niche

How statue-like I see thee stand,

The speaker is floored by Helen's beauty as he sees her standing in the "window niche" (like a nook).

Saying "Lo" is like saying OMG when you all of a sudden see something astonishing.

Helen is standing "statue-like," which means both that she resembles a work of art and that she is not moving at all.

Pssst: this comparison here with the word "like" tells us that we've got a simile on our hands, just in case anybody asks.

Why is Helen like a statue? Is the speaker in one of those reveries you see in the movies where everything seems to stand still?

Could be, but she's also statue-like because she's as beautiful as a work of art—proportionate, perfectly crafted, and just totally hot.

Lines 13-15

The agate lamp within thy hand!

Ah! Psyche, from the regions which

Are Holy Land!