There's no welcome lounge, so no, you won't. And even if you did have star alliance gold,
you still wouldn't get in any lounge
When travelling on Olympic Air, only Miles and Bonus Gold members and Business Class passengers have access to the Lounges.
...
*Νot available for Gold Star Alliance members travelling with Olympic Air.
United and Turkish will earn you miles when flying Olympic, but I don't know if having gold status with them actually gets you in the lounge (there's no mention of such a perk on either website).