Our Ops Manual for A319/320/321 is supposedly pretty similar to Airbus SOPs from FCOM 3, and includes this line during the engine start bit:
In case the electrical power supply is interrupted during the start sequence (indicated by the loss of ECAM DUs) abort the start by switching OFF the MASTER switch. Then perform a 30-second dry crank.
Doesn't seem to allow for the 'suck-it-and-see' kind of discretion considered on some types during this discussion.