First of all, if there were morels to forage in SoCal, the first rule would be not to talk about morel foraging in SoCal.
There have been scarce citings especially of the black morel, but generally you shouldn't try to forage for mushrooms unless you know what you're doing. Foraging field trips are sometimes available through LA Mycological Society with priority given to LAMS members.
Other than that, for purchase, LA Funghi is hopefully at a farmer's market near you. Dirk also has terrific fresh maitake, porcini and truffles. The season is coming to a close and the best morels have already been realized, but he might still have more.