No, I don't have the exact information about the marriage of Philomene Ducharme and Pierre Robillard. Likely, it did not occured in Québec, unless there was a mistake in the register when writing down that marriage.
Such mistakes do happen. As an exemple, I found yesterday in the registers of St-Pie, QC, the following information about a person who I believe is your Philomene:
«June 22, 1838, baptism of Philomene, born yesterday, daughter of Francois Tetreau dit Ducharme and Zoe Parent. Sponsors Francois Parent and ? Lamothe. The father was not present (my translation from French)».
There is a mistake somewhere, because there is no such couple as Francois Tetreau dit Ducharme and Zoe Parent! There was on one side Francois Tetreau dit Ducharme and Catherine Brouillet, and on the other side Noel Charron dit Ducharme and Zoe Parent. Name of the godfather lead me to believe that the second one is the good one, but only a cereful and complete review of this register could help us find the truth. I will try to find more about this in the coming days.
Hence, Philomene is either a Charron-Ducharme, either a Tetreau dit Ducharme. If we find her marraige, we will have the correct answer.