Of course I can just split it (and I will, because you won’t answer quickly enough… ) but at least I’d like to know until I run into a similar problem next time.
Tried that, but after rotating, the geometry doesn’t seem to stick to the surface. Boolean fails. An “Intersection” shows the following curve as a result:
… but hm, that may simply indicate I need to try harder to define the center… (I’ll try some more).
Edit: Tried being more careful defining the center point, and after retrying your sequence of commands, the rotate copy geometry is elegantly in place.
(Btw, I got away without splitting due to the quick answer… )