Artur Wilhelm Nilsson, born -84 11/12 (11 December 1884) in Karl Johan's parish, Göteborg, was a foster child (probably with the carpenter Johannes Odin) until he left for America 30 September 1902.
Source: Göteborgs Oscar Fredriks församlings kyrkoarkiv, Församlingsböcker, SE/GLA/13189/A II a/16 (1899-1907), bildid: 00054146_00065, page 2262, line #20. Link to image at Riksarkivet.
The volume where his birth is recorded is missing among the published records at Riksarkivet (temporarily?)
Since I have a subscription to ArkivDigital I have been able to see the birth record (Göteborgs Karl Johan (O) C:7 (1882-1889) Bild 143) - it shows him born out of wedlock to Elisabet Nilsson - there is however a note that she is the fiancé of A. Nilsson.
Artur Wilhelm moved a lot within Göteborg as a child, it would take some time to piece together the story. I find him with his mother (who is the wife of the absent August Nilsson) and a younger sister, then he's with his father, his mother having died... oh, looks like his dad went to America and left him behind; that's why he is in a foster home.
I'd be surprised if this wasn't him.