I don't think I've ever seen dragons who turn human, but it sounds awesome and definitely not cheating, because in their essence they'd still be dragonish (also, they need to be able to communicate with Elle somehow and turn up on hearings and whatnot. I don't imagine most courtrooms are dragon-accessible.)

I do love stories about humans who turn into dragons - like American Dragon: Jake Long, a surprisingly cool Disney cartoon I can sorta recommend.