It's basically what she ... now he ... identifies as. Often, the most important part of a gender transition is the identity, not the surgery (although the surgery is probably the biggest move). Female-to-male transsexuals pick a name and identify as a man long before they undergo surgery; many start taking doses of testosterone to aid the transition.

So, she is not a lesbian, because she is a he, and he is a man. Identity is more important within our society than biology.