James Thomson was born Scotland around 1780 near Glasgow, Lanarkshire. He married Janet Waddell and had four children named: James, Janet, John and Robert.
Son John emigrated to Canada and settled on a 100-acre farm in the Township of Caradoc in the County of Middlesex
Son James also emigrated on the 27th day of April, 1842, on the “Queen of the Isles”, bound for Montreal later onto the County of Middesex as well.
It appears the spelling of Thomson was changed to Thompson around this time.
I can find John Thompson recorded in Caradoc, Middlesex Ontario, however I am not certain if it is the same John Thomson as no parents are listed nor an area of Scotland where he immigrated from.
Trying to make the connection from the Strathroy Thompsons to the Goderich Ontario Thomsons.