Don't know if this will help or not....
I was able to find, from the Sanborn Fire Map (Vol. 5 - 1914), that the 1500 block of N. Elston was mostly residential at that time (there was, however, a bake shop located at 1538 N. Elston).
Before the street numbers had changed circa 1909, 1520 N. Elston was 459 Elston. I found one Tribune article which was dated August 15, 1891 which mentions a P
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