In non radar enviroment,i.e APP/PROC each clearance must contain clerance limit,e.g
"Clear for ,type of approach or STAR , report LLZ/ILS established. "
LLZ/ILS establishement is not clerance limit but we use it for separation and transfer purspose.
It depends on local procedures but in our cases all approach procedures are published until DH/DA followed by missed approach procedure. So if you lost contact everything is clear until decesion point, if there is no contact at decesion point than reffer to AIP for "lost of communication" procedures/
and yes ,this issue is the big discussion among atcos....