Stephen King Fans discussion

In the fourth story "Danny Coughlin's Bad Dream" page 174, there is the quote "There's an action figure... that he recognizes, thanks to Darla Jean. It's Elsa Oldenburg from Frozen."
So my actual question is, does anyone know where King got the name Oldenburg from? Like I never remembered her having a last name in the movies, so I googled what is her last name, and Oldenburg never came up. Upon googling Elsa Oldenburg, the only things that came up was a great multiverse wiki page (with a drawing of Elsa holding a light saber?), and a lot of fan pages. I couldn't find anything that suggested this is Elsa's official last name.
Someone please help if you have any ideas or answers. I'm going down a rabbit hole. I felt like I opened pandora's box with this wiki page.

Elsa's last name has been translated as Agnarrsdstter or Idunasdatter based on historical context and naming patterns of Norway in the late 1800s.

It was probably a matter of King seeing or hearing of an action figure named Elsa Oldenburg and assumed it was Elsa from Frozen.

But given that King's DT mythology covers a lot worlds that are "like" ours, there could be one out there where Oldenburg IS Elsa's last name. Though no mention of it taking place on anything other than they keystone world is made in the story.

I always felt the DT myth was just a convenient way to explain away such goofs, anyway.