Lorenzo sealed his place at the head of the pack on his final lap of qualifying as he posted a best circuit of one minute 21.202 seconds in scorching conditions.
Championship leader Casey Stoner also left it late before he snatched second place, 0.072secs behind Lorenzo, with the Australian's Repsol Honda team-mate Dani Pedrosa third on the grid.
The home fans in California were given reason for cheer as Ben Spies claimed fourth place, although it may have been better for the American after he was unable to return after crashing out with five minutes left in the session.
Lorenzo's high-speed spill in this morning's final practice session was more spectacular though, as he was launched into the air and across the gravel.
The 24-year-old was somehow unhurt and then displayed his champion-quality as he shook off the setback to clinch pole and continue to pile the pressure on Stoner.
The Australian has seen his championship lead reduced to 15 points by Lorenzo after the Spaniard has beaten him in the past two rounds and Lorenzo will fancy his chances of eating further into that gap after his performances so far this week.
Further back in the field, the Italian trio of Marco Simoncelli, Andrea Dovizioso and former champion Valentino Rossi were lined up from fifth to seventh.
Rossi's performance offered Ducati some hope, after he had initially struggled in the session, before finishing 1.033 behind Lorenzo.
The Italian had only managed the 11th-best time after yesterday's free practice but snuck onto the third row along with his fellow Ducatis of Hector Barbera and Nicky Hayden.
Great Britain's Cal Crutchlow rounded out the top-10 on his Monster Yamaha.