On what date was the tournament played that eneded with a winning score of +6 (74-71-70-71=286) and margin of victory of 2 strokes, and with Arnold palmer as the runner-up?
CREATE TABLE "senior_pga_tour_wins_24" (
  "date" text,
  "tournament" text,
  "winning_score" text,
  "margin_of_victory" text,
  "runner_s_up" text
);
SELECT "date" FROM "senior_pga_tour_wins_24" WHERE "runner_s_up"='arnold palmer' AND "margin_of_victory"='2 strokes' AND "winning_score"='+6 (74-71-70-71=286)';