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.
I think that these are the wrong way round.
"Placename Radio" is A/G and has no control, just provides information
"Placename Information" can control you on the ground and onto the runway for T/O at your discretion.