The lyric mode, which is most associated with poetry, as we associate the narrative mode with fiction, can occur in any genre. Poems, plays, essays, stories, employ a variety of modes other than what might be thought of as their signature mode -- in other words, poetry isn't always in a lyric mode, or fiction in a narrative mode, nonfiction in an expository mode. You can define the lyric by comparing it to the narrative. The narrative mode is linear, chronological, and because of chronology -- the old first this happened, then that happened -- it implies cause and effect. The lyrical, by contrast, is the mode of dreams: associative both in terms of image and sound, so that we can get from one idea to another via assonance, alliteration, rhyme. Time in the lyric is subjective: you can speed it up, slow-mo it, flash forward. Often in stories what is called the epiphany is actually a switch from the narrative to the lyric mode. Joyce's "The Dead" offers a classic example of this: the story is in the narrative and dramatic mode for most of its length, but at the very end, closure involves a leap into the lyric complete with images of falling snow and the f-sounds Joyce employs.
[from an interview with Stuart Dybek by Jeanie Chung, AWP Chronicle, Oct/Nov 2005]
This was in response to a question about "lyric fiction," but I think it's a decent definition of "lyric" and "narrative" in general, and I like what he says about switching from one mode to the other. Since M. writes some fiction as well as poetry, I think this might be a particularly useful discussion for her -- and for me, too (ooh, selfish tutor, talking about stuff that's useful to me *grin*). I also like that he parallels "assonance, alliteration, rhyme"-- and the associative in general -- in the lyric with chronology in the narrative, as ways of getting from one place to another. That just kind of makes a little light bulb go on for me. Even though it's pretty basic stuff, I hadn't seen it quite this clearly before.