Yogibar, Tschurschak is probably the German form for Chuchak, the place listed by Soviet sources, a village situated on the south side of the Sivash. See link below:
http://www.maplandia.com/ukraine/res...-krym/chuchak/
Thanks, Nikita, for your answers. If the time difference is two hours, do you agree that Lavrenov was probably shot down by Lt Walter Wolfrum of 5./JG 52 at 1402 hrs German time/1605 Soviet time ?