So I just took the coffee cup STL and loaded into the latest Cura myself, rotated in 90 degrees so it was standing upright. Without changing anything else, I ended up getting the layer changes on a few difference places over the print (I'm seeing this just by analyzing the G-Code using http://gcode.ws), depending on the layer height. It starts to the right of the handle and after a while seems to sort-of stabilize almost on the opposite side of the handle and on the right side of the actual handle, before the handle separates from the cup body.

All in all, it will likely have come out decent, but certainly not under the handle as you have. This I guess is because Cura will start the new layer close to where it finishes it's previous layer by default. In other words: it depends on infill percent/pattern and model location on the build platform.

I figure this is because you've added support. This causes the print head to get a "closest" start of the new layer exactly under the handle (because that's where the support material are). So going as far as calling it "lucky", no. The support placement actually helps Cura put the Z-scars in a good place on this model. On another model, it might be the exact opposite.

(PS: I use Cura for all my slicing and I like it a lot -- but I don't feel like the software actually gives me much control about the Z-scar placement)