The governor and lieutenant governor shall be elected at large within the Commonwealth for a term of office of four years. The governor and lieutenant governor shall be elected jointly with each voter casting a single vote applicable to both offices. After the Commonwealth Election Commission certifies the results of a general election and if no candidates receive more than one half of the total votes cast and counted for the offices of the governor and lieutenant governor, on the fourteenth day thereafter, a runoff election shall be held between the candidates for governor and the lieutenant governor receiving the highest and second highest number of votes cast and counted for those offices. Runoff election procedures shall be provided by law. No person may be elected governor more than twice.