Dear Cindy, We are indeed related. My 4x great grandfather Antoine Lagarde dit St.Jean is your Thomas' brother. My Antoine married a Esther Cardinal whose mother's maiden name was Jamme-Carriere. Possible coincidence? I have never found any Thomas in the Lagarde family so I can't help you much with him but if Paul and Marguerite are his parents then I can give you the Lagarde line going up and the wives lines as well! As for the other St.Jean in your line I cannot find anything on him but I will watch for any info on him!
Here is the line for Paul and Marguerite!
1 Abraham LaGarde married Marguerite Charlospin in France children: Pierre LaGarde
2 Pierre LaGarde married Marie Chaton Feb 05,1667 France children: Pierre LaGarde
3 Pierre LaGarde born 1673 married Genevieve LeRiche married ABT 1700 LaRochelle,Aunis,France children: Jean-Baptiste LaGarde dit St.Jean
4 Jean-Baptiste LaGarde dit St.Jean born 1709 France married Marguerite Martin dit Ladouceur Aug 11,1733 Montreal children: Jean-Baptiste LaGarde dit St.Jean Francois-Antoine LaGarde dit St.Jean Louis LaGarde dit St.Jean Laurent LaGarde dit St.Jean Anonyme LaGarde dit St.Jean
5 Francois-Antoine LaGarde dit St.Jean born Aug 03,1736 Montreal married Marie-Elisabeth Mondoux Jan 23,1759 St.Francois-du-Lac,Quebec children: Antoine LaGarde dit St.Jean Paul LaGarde dit St.Jean
6 Paul LaGarde dit St.Jean born 1768 married Marguerite Desloges dit Poirier Jan 28,1793 St.Eustache,Quebec children: Marie-Louise LaGarde dit St.Jean Antoine LaGarde dit St.Jean Thomas LaGarde dit St.Jean ( yours )
If you would like the lines of the wives just let me know and I will send them too.