Generally speaking:
If there is an Air/Ground service - ie Placename Info - they can't tell you what to do, so start -up would be at your leisure.
If there is a FISO - ie Placename Radio - then they can tell you what do do on the ground, except when on the runway. So you might not be able to start up without their permission.
And, of course, a full ATC may even have a dedicated Ground frequency.
In practical terms, just ask when you pay your landing fee!