From this document here: http://www.forms.ssb.gov.on.ca/mbs/ssb/forms/ssbforms.nsf/GetFileAttach/014-9998E-82~1/$File/9998-82E.pdf, which is at all Service Ontario offices have, says "Written confirmation from Citzenship and Immigration Canada that you are eligible to apply for permanent residence in Canada"
I used that point to apply for OHIP, since my letter says "You have met the requirements for eligibility as a sponsor. Accordingly, the Application for Permanent Residence for your relative(s) has been forwarded to a visa office abroad for further processing."
They re-read it a few times, and asked a few co worker agents whether it's acceptable, and everyone said yes.
I put the date she last landed in Canada, which was a year and a half ago.