[2] He had practiced at the office of Espen Tharaldsen (Arbeidsgruppen Hus) in Bergen (1982–1983), Ralph Erskine in Stockholm (1983–1984) and David Sandved in Haugesund (1985).
[4] Thorsen led several award winning design competitions for public buildings around the world.
He led the Snøhetta teams designing the museum built for the Winter Olympics in Lillehammer, Norway,[1] the 2007 Serpentine Gallery temporary Pavilion in London designed with Olafur Eliasson, the new Bibliotheca Alexandrina library in Alexandria, Egypt,[2] and the new Oslo Opera House in Oslo, Norway.
Thorsen had been a professor at the Institute for Experimental Studies in Architecture of the University of Innsbruck since 2004.
[citation needed]He will Chair the Holcim Foundation Awards 2025 jury for region Europe.