Hi John, this is possibly a lead for you on the 1891 census where Mary Dickson is living in Lanark with her son Arthur aged 15 yrs, Mary is aged 40 yrs, head of household.
On the 1881 census, the only Arthur noted on the census records with grandmother "Mrs" Dickson and other grandchildren. Arthur 5 born Lanark, Flora Dickson 10 b. Lanark and Catherine 2 b Lanark
Mrs Dickson is born 1817 Tobermory, Argyllshire. (possible mother of Mary?) is research the other children living in the household with their grandmother on the 1881.
Paul, the surname may be Clancy