AC 864 then BA 750 at Heathrow
Montréal → London → Geneva
Timetable, London time
07:10AC 864 from Montréal at the gate
19:30BA 750 to Geneva leaves the gate
12 h 20 apart on the timetable
BA 750 leaves 12 h 20 after AC 864 arrives on the timetable: more than half a day, so not a connection we count.