GMDS, noelbaba's quotation of the eTurbo news article by Unal Basusta is laced with what appears to be noelbaba's opinions. Basusta's reporting, while itself containing some conjecture and opinion, has no sentence about the captain needing to be present in the cockpit during severe thunderstorms.
The French press (Figaro, Le Monde, France Soir) in reporting on Arslanian's conversation with aviation reporters on August 31 makes no mention of Arslanian saying anything at all about where the captain was during the final minutes of AF 447.