A bunch of us were discussing this and we're not entirely sure it's originally Flandre. I trace and modify images myself so some common problems stuck out to me. Things like her outfit being a tad different, her having no wings, and the fact that Lev is coming out from under her skirt like a tail, and doesn't quite look the same on the end.
hmm....doesn't seem to have alot of the trademark features of flandre, no wings, clothes different, and of course no puffy touhou hat..having said that, i'd say no, it's not originally flandre but a edit. either that or the artist decided to exercise some artistic changes to her design ;p