If a person is called for Aliyah to recite the Torah blessings, and does not habitually wear a Tallis, but dons one on for k’vod ha-tzibbur, does he have to say lehis’atef b’tzitzs?
If you borrow a tallis from one of the congregants, you should not recite a blessing before wearing it. However, if the tallis belongs to the shul, you should recite the blessing before wearing it.
Sources: Mishnah Berurah 14:11. The difference is that a communal tallis is given to the shul with the intention that all those who wear it should acquire it to be theirs, and the wearer is therefore fully obligated in the mitzvah, and must recite a blessing. This is not the case for a regular borrowed tallis, which does not involve a full obligation of tztitzis, and a blessing is therefore not recited.