On the very first sheet of the 1840 parish register of Notre-Dame-de-Bonsecours, Montebello, Quebec, appears two Groslot marriages. Translation of certain parts:

1840 Feb 24 …
the marriage of Pierre Leduc,
  adult son of Pierre Leduc
  and of Marguerite (Laberd?)
  of St. Clement,
and Hèléne Groslot,
  minor daughter of
  Pierre Groslot & Marguerite Coutenais
  of this parish
In the presence of 
Paul Sabourin, servant of groom's father,
Pierre Di__, groom's friend,
Pierre Groslot, groom's father, &
Etienne Parent, bride's friend

1840 Feb 24 …
the marriage of Michel Groslot, farmer,
  [adult son of Pierre Groslot, farmer]¹
  and of Marguerite (Laberd?)
  of this parish
and Hèléne Tivierge,
  minor daughter of
  Jean Baptiste Tivierge, farmer,
  and of Geneviève Joly
  of this parish
In the presence of 
J. B. Tivierge, bride's father,
Josephitte St. Denis, bride's friend,
Pierre Groslot, groom's father, &
Joseph Lefebvre, groom's friend

Groleau, Grosleau, Grosleaux, Groslot, & Grolot are all pronounced the same and all are used in different parts of the records back then.

These names appear in seventeen other baptism, marriage, and burial records in that book (1840-1851)

¹the priest must have copied notes from another paper and skipped a line,
which I inserted with [brackets]