Since you moved from Quebec, you can send your kid to public French school, it's much better than French Immersion. Don't worry too much about his English, he will catch up very quickly in Ontario's English environment. Kids speak English during recess time here.
Ontario district school board:
http://www.osstf.on.ca/www/links/districtschoolboards.html
GTA public French school board:
http://www.csdcso.on.ca/
If you are catholic, here is GTA Catholic French school board:
http://www.csdccs.edu.on.ca/
Ontario district school board:
http://www.osstf.on.ca/www/links/districtschoolboards.html
GTA public French school board:
http://www.csdcso.on.ca/
If you are catholic, here is GTA Catholic French school board:
http://www.csdccs.edu.on.ca/