Tear the endive and lettuce into bite-size pieces and place in a salad bowl. In a small bowl, combine the walnut oil, vinegar, and lemon juice. Beat with a wire whisk until well blended. Season with salt and pepper to taste. Drizzle over the greens and mix well. Arrange the greens on individual salad plates and top each serving with a portion of toasted walnuts, cherries, Roquefort cheese, and chives.