The family name Larocque  has its origin in Gascony and other area of in the south west of France between the Rhône River and the Pyrenees.  In this part of France there are many village with the name Laroque or has the word Roque in i's name like Roquelaure for example.  On this WEB site I made a list of thes villages. In the Occitan language the word Roque is said Ròca. In a book of Gascon toponymy written by Benedict and Jean-Jacques Fénié it is said that the word Ròca not only designate a rock or a boulder but also a rocky heights fortified or not. Documents of the time written in Gascon call our ancestor de la Roca meanwhile in Latin we speak of Ruppe which mean Rock. Nobili Johanni de Ruppe, domino dicti loci de Ruppe & de Ordano. 
In the surrounding of Ordan Larroque, we can see the remnants of Gallo-Roman towers or rocky piles that probably gave the village it's name. The word Roque has probably passed to the usual French language meaning a fortified tower. In the etymological dictionary of family name and surname of France we can read that Laroque (Rock or Boulder) was used to designate a fortified castle build on or near a rock. The word "Roque" has disappear from the French language. The word Roque was borrowed by the English language to name the tower in the game of chess, the Rook. 

In Canada, the name Laroque was given an extra C but at the beginning it was written LaRoque or La Roque. We believe that the notary and law writer, because they were from the area of Paris added the C as this was the way this name was written there. In the parish record the name has took many spelling like Roc, Rock LaRoc etc. 

As for Roquebrune, the name come from a village of Gascony located just a few kilometres south of the town of Vic Fezensac. It is the word Roque with the colour Brune (Brown). The name, when englicized, became Rockbrune, Rockburn, Rockburne and Roburn. There is also an other town in France called Roquebrune that use to be part of the Principality of Monaco. 
Two of the four Larocque ancestors, Guillaume and Antoine originated in Gascony. François, we believe was from  Normandy . As for Philibert Couillaud (pronounce Koo-Yo, in French two L's following an I sounds like a Y) dit Roquebrune, the Canadien ancestors of more then  80% of the North American Larocque all tend to prove that he was from Nevers. During all his adult life in Canada, not once did he declared to be named Larocque to a Notaire for a contract or to a priest officiating a religious ceremony. Philibert Couillaud declares also not being able to sign at the bottom of the documents  It is from the first generation of Canadien that the children of Philibert Couillaud dit (aka) Roquebrune opt for the Larocque surname. It is sometime Larocque, or Laroque and sometime Laroquebrune. It remains to be investigated why the Couillaud's children decided almost unanimously for the name Larocque otherwise we would still be Couillaud. Many kept the name Roquebrune until the 20^th century at which time they changed to Larocque.  There are still many Roquebrune. The name became in English Rockburn and Roburn.

Two interesting statistics from the Canada411 directiry index. First thing is that almost 50% of the Larocques live outside Quebec. Secondly, 97% are Larocque surnames with or without the C or its English version like Larock.  This leaves a 3% of Roquebrune and its variation.  There are no Couillaud listed in this Canada411 directory. 
According to statisticians, each family name in the 411 directory should be multiplied by 3 to obtain an approximate number of people with any given name. In that case there would be about 15,000 Larocque in Canada. See the table below. (Updated March 23, 2010 )
 

The surnames Larocque, Laroque, Couillaud, Roquebrune by the number of birth in  France between 1895 et 1990. The Larocque births between 1891 and 1915 were mostly found in Britany, but also in the  Nord (59), in Paris (75) and the surroundings (92, 93, 94).