Pupuseria Lorenita's has moved across Rte 1 and a few blocks north to 7731 Washington Boulevard in Elkridge.
Thanks to Cash, who first mentioned the move in a comment. The truck is still parked outside a store called Paco's Paints. It still serves up tacos that rival any stationary restaurant. You have to stand next to the traffic, but don't be intimidated. The folks speak English, and you can enjoy the tacos in the privacy of your own car!