As I understand it, a new character has access to the grimoire of the
organization where he learned sorcery, so the number of spells avail-
able to him depends on the number of spells in the organization's gri-
moire and on the organization's rules for learning spells from its grimo-
ire - two setting specific factors, so in the end it is a referee decision.
The way I handle it, a character starts with three or four spells, and
has to serve the organization well to be allowed to learn any additio-
nal spells from its grimoire.
"Mind like parachute, function only when open."
(Charlie Chan)