Some ideas... did you see the headstone yourself and make sure that spelling is accurate?
The name of the cemetery includes 'Valders' a spelling variation for Valdres area of Oppland, Norway. Perhaps your guy was one of a group of Norwegians from that original area? (Within Valdres region are two parishes by the name of Aurdal...)
The 1900 and 1910 US censuses would give you information as to what year he emigrated from Norway - that would help in searching databases of emigrants from various Norwegian ports and knowing which Norwegian census databases would be appropriate to search.
Old church records where he settled in WI may still survive. A Lutheran minister often recorded the names of the parishes in Norway where a new member of the congregation had originally been baptised and confirmed.
Checked for all obituaries published when he died? Small town US newspapers were sometimes quite informative about the deceased.
"Arnoal" may not be a town name at all. It could be the name of a farm in Norway.