Here is the link:
http://www.immigration-quebec.gouv.qc.ca/en/informations/arrima/invitations.html
I highlight here: These invitations allow persons invited to submit an application for permanent selection in order to obtain a Certificat de sélection du Québec (CSQ - Québec Selection Certificate) within an average period of 6 months.
The 6-month period begins on the date when all the information required to process your application (forms and documents) has been received and added to your file. These persons can then submit an application for permanent residence to the Government of Canada.
In fact, this time period is still not clear. Just imaging that, everytime they require additional documents from us, the
6-month period could re-count again and again.