gs: that's a much better shot of the Mauretania, showing its full size. The same coupe seems to be parked in front in both your shot and in the one I found--there is a series of shots of Rossmore in the LAPL collection all apparently taken at the same time. The series also includes another Deco building up the street by the Mauretania's architect, Milton J. Black:
LAPL
590 N. Rossmore
Today:
Google Street View
Google Street View
Milton Black is known for a number of small Deco building around Los Angeles. A few others attributed to him:
LAPL
A 1936 building on the northwest corner of S Hobart and W 9th
Today:
Google Street View
The 1940 Westwood Ambassador Apartments, 10427 Wilshire:
LAPL
LAPL
Only the wall remains:
Google Street View