Hi
Daniel,
Helsing is a newer spelling of Hälsing (same pronunciation) as in the place names Hälsingland (Swedish county), Helsingborg (Swedish town), Helsingør (Danish town) Helsingfors/Helsinki (Finnish capital) and some smaller places like Hälsingbacken, Hälsingen, Hälsingfors, Hälsinglund, Hälsingmarken, Hälsingtorp etc.
The place names derive from the word "hals" which means "neck, throat" nowadays but meant "narrow river, brook" and "tongue of land, hook" earlier.
Some of the places might be named Hälsing-... because people from Hälsingland were the first to settle there and not because of any "hals" around.
Nowadays the word "hälsing" alone means "man or woman from Hälsingland (Sweden)" in Swedish.
Regards,
Satu