In a skillet, heat oil over medium heat for 30 seconds. Add onions, celery and carrots and cook, stirring, for one minute. Add stock, white wine and cook, stirring until carrots are softened, about 7 minutes. Add thyme, bay leaf and flour (or arrowroot) and cook, stirring, until mixture comes to a boil and thickens, about 4 minutes. Drain reserved potato and add to the mixture. Season to taste with salt and pepper.