Plebejus (lupini) monticola
The type locality for monticola is Pasadena (Victor Clemence collected them from the "Arroyo Seco" in 1907 - a lectotype has been designated), and my photos from up San Gabriel Canyon - not far from there - match the type specimens very well. That's a good reference point, but straying from there can lead to confusion, as these will look a bit different to the south or the north. To add to the complexity, what we've been calling lupini monticola is almost certainly a different species from lupini chlorina. There are places where the two entities both fly (as in the Tehachapis), monticola flying earlier and using fasciculatum, and chlorina flying next using umbellatum. According to John Emmel (pers. comm), chlorina larvae are still eating in May while monticola is flying in the Tehachapis. Ken Davenport, in his Kern-Tulare publication, also mentions lower elevation monticola on fasciculatum flying earlier than the mid-June to July chlorina on umbellatum at higher elevations; he mentions worn monticola flying with fresh chlorina.
For now, here's my bottom line on these: monticola is likely its own species, not a subspecies of lupini; it is associated with E. fasciculatum; it flies ca. May in a single brood; and females will range from blue to brown depending on where you find them.