 She travelled to Germany for further voice lessons with Paul Lohmann at the Musikhochschule Frankfurt and Franziska Mattienseen-Lohmann in Düsseldorf.In 1956, Bjoner made her first professional appearance singing the role of the Third Norn for a radio broadcast of Richard Wagner's "Götterdämmerung" produced by the Norwegian Broadcasting Corporation and starring Kirsten Flagstad as Brünnhilde.In 1957 she made her stage debut as Donna Anna in Mozart's "Don Giovanni" with the Norwegian National Opera; reprising the role later that year for her debut at the Wuppertal Opera.