Joseph is on the 1900 Census as a widow living with son Olesime. So if this is the right Joseph, then Louisa died between 1880(she is on Census with Joseph)and 1900. I couldn't find her death record. The death record of Joseph in 1904 - looks to me like he was buried in Canada. I searched the Boston Globe for obits and didn't find any. You might try the Worcester library and see what they have.

Margaret