Information found on 1901 & 1911 Census,Google 1911 Irish census to find,free.
1901 Charles 60 and Jane 50 Murtagh at College St, Cavan
Found nothing for Arthur in Cavan,so tried a all Counties search. Found a Arthur Murtagh born in Cavan on 1901 & 1911 at Derryaghy,Antrim with wife and children. On 1911c he is 37, 2 of the children have names of Charles and Jane.