Short answers, pulled from the story.
The Falaise pocket closed on the 21st of August 1944 when tanks of the 4th Canadian Armoured Division linked with Polish forces at Coudehard. All German soldiers west of Allied lines were either dead or captured by the 22nd of August.
Lieutenant General George S. Patton took command of the Third Army on the 1st of August 1944. His units advanced rapidly toward Alençon without meeting significant resistance before the pocket formed.
Polish battlegroups occupied part of Hill 262 also known as Mont Ormel during the night of the 19th of August 1944. The Poles repulsed heavy assaults from the 352nd Infantry Division and elements of the 2nd SS Panzer Division by mid-afternoon on the 20th of August.
Canadian casualties totaled nearly 5,500 men including 1,470 killed and 177 captured during the operations. The 1st Polish Armoured Division listed 1,441 casualties including 466 killed while fighting near the pocket.
General Bernard Montgomery accepted General Omar Bradley's proposal to stop at Argentan after a telephone conversation on the 8th of August 1944. Historians note that Bradley halted Patton not due to fear of clashes with British forces but because American units lacked means to defend an early blocking position against powerful German formations still operational.