CREATE TABLE table_23408094_14 (tournament_at_which_lead_began VARCHAR2, player VARCHAR2, titles_won_at_point_of_lead VARCHAR2)

At which tournament did william renshaw begin his lead when he had won 7 titles?
SELECT tournament_at_which_lead_began FROM table_23408094_14 WHERE player = "William Renshaw" AND titles_won_at_point_of_lead = 7
SELECT "tournament_at_which_lead_began" FROM "table_23408094_14" WHERE "William Renshaw" = "player" AND "titles_won_at_point_of_lead" = 7