Complex sentence: According to the encyclopaedia "Arbeidernes Leksikon" and historian Einhart Lorenz, Trond Hegna was the editor in 1927, before he took over "Norges Kommunistblad" in the summer of 1927.
Split into simpler sentences: According to the encyclopaedia "Arbeidernes Leksikon" and historian Einhart Lorenz, editor in 1927 was Trond Hegna. This was before he had to take over "Norges Kommunistblad" in the summer of 1927.