I found a Civil war service biography for someone I believe is Erland Berge's first cousin, (an older first cousin) who is son of Ole Berelsen, and was born Morten Olsen Lodengaard in østre (east) Gausdal, Oppland Norway. His immigration information might give a clue to Erland's parents path too.
WI 30th Inf Co D. Residence: Martell, Pierce County, Wisconsin. Born “Morten Olsen Lodengaard” on 22 Aug 1827 in Østre Gausdal, Oppland, Norway, son of Ole Bertelsen Lund and Sofi Mortensdatter. He came to America on the bark “Preciosa”, which sailed from Drammen, Buskerud, on 2 Jun 1849 and arrived at New York on 26 Jul 1849. He came to Martell Township, Pierce County. Civil War: Farmer. Age 35. Unmarried. Blue eyes, light hair, light complexion, 5’8½”. Enlisted for three years on 21 Aug 1862 at Martell. Mustered 21 Oct 1862 at Madison, Wisconsin. Private. Mustered out with his regiment at Louisville, Kentucky, on 20 Sep 1865. Post war: He was married on 30 Mar 1873 to Maren Sophia Peterson. Sources: (WHS Series 1200 box 140-13; red book vol 35) (Larsen p57) (Naeseth-Hedberg ’49-1878)
I also found that the list of people who emigrated from Gausdal is online (by googling Lodengaard) and that Erland's parents are listed on it at this web page:http://www.disnorge.no/cms/en/navneliste-over-folk-som-utvan...
1848 April 17,
Hmd. Anders Bertelsen Lodengard 49
Kone Sophie Olsdtr. 40
Børn Berthe 13
He is a tenant farmer (not owning his own farm) and she is kone, his wife. Three daughters whose births I found indexed at familysearch.org for them. Berthe, Rannig (there are other spellings of that) and Anne.