Looking at the name Soule and the clues that come from the name.
First clue french style spelling and sound of the name. Do we look to France, maybe or another country using the french language.
Looking for a second clue in the name Soule it self.
1) possibly it means the fish Sole In english the the fish is Sole like it sounds. In dutch it is Tong. Also a flounder fish name Schol. However the french speaking sound is the same as English.
2)But many names also reference a place, so we should look for places that sound like "Soule" or in the native tongue of that country. In looking towards the Netherlands. It appears that there is a Tongeren, in Zeeland and a Tongerlo in Belgium. But wait, we should look back 400 plus years to see if any other places use Soule or sound "Sole" When we do this we find 3 place in a Belgium Book or royal places and nobilty. Here these 3 places ( There is the old land of the hamlet of Solt (possibly a small Fiefdom ( Heerlijkheid) in the 13th and 14th century, was later distributed over Maaseyk, Gruitrode and (a small part ) over Opitter.Till the end 19th century there were quarrels over its borders with the nearby villages, Most of the land was quite infertile moorland, exception the borders of the small river the "Itterbeek". Maaseyk-Solt (Neersolt) measured only 145 hectares and had in 1650 only 15 houses, in Opsolt (Gruitrode) 25 houses In 1958 the number of houses in Neersolt had increased to 38 houses with 224 inhabitants,