Who is lancelot's mother?

his mom died so he was raised by the lady of the lake

No, his "mom" did not die in his childhood. He was taken from her to be raised by the Lady of the Lake after the death of his father King Ban. Queen Elaine (Vulgate Version of the Lancelot) was distraught at losing her son, but was reassured one day by a passing "black friar"-who later turns out to have been a famous knight before entering the monastery- that her son is alive and being well-cared for, so she is consoled.