Positive mitzva #7 = ומקדשי תיראו We have a positive mitzvah to have an extra sense of fear and awe of Hashem in His holy places. The basic understanding of this mitzvah is that it is talking about in the mishkan or Beis Hamikdash but most poskim hold it applies now a days in our shuls and yeshivas, therefore one should not shmuz mundane talk in shuls or yeshivas and certainly not speak loshob hara or rechilus. You are making your speech or listening to loshon hara even worse then it already is when doing it there because you are showing you have no care for the King of all Kings who focuses his holiness in these places and you are totally ignoring his laws in His “face” lihavdil.
Positive mitzva #8: והדרת פני זקן There is a positive mitzva to show special respect to the elderly and a sage and by speaking any form of lashon hara about them not only does one transgress the prohibition of lashon hara but also does not fulfill this mitzvah. If one hears the lashon hara and does not stop it or protest it and even accept it he also transgresses this positive mitzva, whether he is standing in front of the elderly person or sage or behind his back. And if the person is both elderly and a sage the transgression is double-fold.
Positive mitzva #9 וקדשתם There is a positive mitzva to treat a kohen with extra respect for example giving him the first Aliyah to the Torah. If one speaks or accepts lashon hara about a kohen he also transgresses this mitzvah, just like by the previous mitzvah.