AC 511 then QR 8187 at O'Hare
Toronto Pearson → Chicago → Houston
Timetable, Chicago time
19:58AC 511 from Toronto Pearson at the gate
16:40QR 8187 to Houston leaves the gate
20 h 42 apart on the timetable, overnight
QR 8187 leaves 20 h 42 after AC 511 arrives on the timetable: more than half a day, so not a connection we count.