Here's what articles 2 and 3 of the regulations of the Moldovan Parlament say:
Article 2. The Inaugural Session of Parliament
(1) The inaugural session of the newly elected Parliament is presided over by the oldest elected deputy. Later, after election, it is presided over by the President or one of the Vice Presidents of the Parliament.
(2) The chairperson of the session invites the President of the Constitutional Court to submit a report on the election results and on validation of the mandates of the deputies elected.
Article 3. Date on which Parliament is constituted
Parliament is considered legally constituted from the date of the inaugural session.
Please bear with me; I'm going to have to pick out a few fine points here:
a. The 28th of August is the last date on which the inaugural session can be held (30 days after the July 29th election)
b. Article 3 above implies that the inaugural session occurs on a single date, and cannot be spread over multiple dates.
c. Article 2 above implies that the election of Parliament's leadership must take place during the inaugural session, as it requires the second part of the session to be presided over by either the elected President or one of the Vice-Presidents.
The upshot of (a)-(c) above is that Ivan Calin and the communist party cannot prolong their dictatorship over Moldova by terminating the session immediately after conclusion of the formalities.
The law requires them to hand over control over parliament to the new majority, and they must do it tomorrow.