Shemiras Halashon Halachos
Hilchos Lashon Hara, Opening – positive commands (7) If one speaks lashon hara in a beis hamedrash or shul, one transgresses the positive command of (Vayikra 19:30), "You shall fear My temple [mikdashi]," and our beis medrash too is considered a mikdash. Therefore, one may not make financial calculations in a shul, excepting for those of a mitzvah such as of the charity box, how much more is laughter and empty talk forbidden, and how much for is it forbidden to speak lashon hara and rechilus inside them.
Even people learning on a permanent basis in a beis medrash who are permitted to eat and drink there, transgress, "You shall fear My temple," if they speak words of levity and frivolity, lashon hara or rechilus.
Hilchos Lashon Hara, Opening – positive commands (8) If one speaks lashon hara about a old person and derogated him to his face, one transgresses the positive mitzvah of (Vayikra 19:32), "You shall honor the face of the old person," which means that it is a mitzvah to talk respectfully in front of him, and if one denigrates him, one is certainly not honoring him.
Speaking lashon hara against a Torah scholar, even if he is not old, is a transgression of this mitzvah, since the "zaken" mentioned in the verse refers to a Torah scholar as well. If he is both old and a Torah scholar, one has a double transgression of the mitzvah.