Where and when did the straight block letter LEGO logo appear on brick studs?
NOTE: from 1949 to 1954 "LEGO" was printed INSIDE the brick.

LEGO appeared on the studs for the first time in the late 1954, then it was re-designed a lot during the years, becoming the stud we all know. 

The not-italic stud of the photo was produced between 1960 and 1963. You can easily exclude 1963+ noticing that it's not the same exact plastic of the modern bricks (ABS was adopted in 1963).

Hope this helps. 
P.S. I'm a huge LEGO collector and I'll be glad to share my expertise here and learn from other passionate people.