If you are a Warlock, then ALL your abilities come from your Patron... NOT just the sub-class specific ones. So you can still choose your Patron at Level 1, and the abilities and spells you get as a Level 1 Warlock come from that Patron. I mean, it's not like there's a generic "Warlock pool" of spellcasting and invocations that characters tap into for all their standardized Warlock features and it's only the "sub-class specific" abilities that come from the Patron. That's just silly. The Patron gives the Warlock all their abilities-- generic or subclass-specific.