I would suggest you route via DVR-KONAN-KOK; KONAN is the border and the limit of the Ostend TMA. You need to call a few minutes before entering and be given clearance to enter the controlled airspace. Ostend APP on 120.60 will take good care of you.
No need to call Lille if you take this route. Koksijde have active SAR military helicopters standing by day and night.