If the lieutenant-governor succeeds to the office of governor, or if the lieutenant-governor dies, resigns, refuses to serve or is removed from office, the president pro tempore of the senate shall, upon taking the oath of office of lieutenant-governor, be lieutenant-governor of the state until another is chosen at the next regular election for lieutenant-governor and is duly qualified. Within fifteen days of the administration of such oath the senate, if the general assembly is in session, shall elect one of its members president pro tempore. In case of the inability of the lieutenant-governor to exercise the powers and perform the duties of his office or in case of his impeachment or absence from the state, the president pro tempore of the senate shall exercise the powers and authority and perform the duties appertaining to the office of lieutenant-governor until the disability is removed or, if the lieutenant-governor has been impeached, he is acquitted or, if absent, he has returned.