The church is located at 6805 de Marseille St in downtown Montreal's east end.
Quebec's Premier-Designate Pauline Marois said she wishes to attend the service.
Blanchette, 48, was at the stage door of the Metropolis concert hall with David Courage, a colleague, just before midnight on Sept. 4 when a man approached the door holding a gun.
Both Blanchette and Courage, who survived the attack, were shot. The stage door of the building was then set on fire.
Blanchette was pronounced dead at the scene.
PQ Leader Pauline Marois, who was giving her victory speech just metres from the other side of the door at the time of the shooting, proposed the idea of honouring Blanchette with a state-sponsored ceremony when she met Thursday with outgoing Premier Jean Charest, and he agreed.
Legislature's flag will be at half mast
Ginette Jean, Blanchette's mother, said Marois and other PQ MNAs were in touch with her and the family agreed to the special funeral, usually reserved for public figures as well as police officers slain in the line of duty.
"I think he deserves that," she said.
The government's protocol office announced Friday evening that the ceremony will take place Monday at 2 p.m. at Saint Donat Church in east-end Montreal. The flag atop the provincial legislature will fly at half mast for the day.
Jean described her son as a good man who may have prevented a large-scale tragedy. "He may have given his life to save others. That's all I can say."
She also said the family isn't questioning why security at the venue didn't prevent the attack, as the emcee of the party publicly did Thursday in an interview with Radio-Canada.
"The law will do its work," she said. What's done is done. We can't change that."
There's no word on when Blanchette's funeral will be held, but his mother said the family would like it to be accessible to the public.
A spokesperson for the Quebec government's protocol office said Friday the office is involved in planning the commemorative ceremony, but final decisions about whether it will be open to the public and the media rest with the family. The spokesperson said details about who will pay for what costs still have to be worked out.
Benefit concert in the works
Équipe Spectra, the production company behind events like the Montreal International Jazz Festival, is organizing a benefit concert in memory of the 48-year-old technician.
The date is not yet fixed, but funds raised will go to support Blanchette's four-year-old daughter.
The police investigation into the election night incident is ongoing.
The Quebec coroner's office confirmed Friday that there would be no formal inquest into the incident, saying the police investigation and the possible trial will be sufficient.
Richard Henry Bain, a Mont Tremblant-area businessman, has been charged with 16 offences related to the shooting, including first-degree murder. He is scheduled to appear in court again in October.Suggest a correction