All backups have LSN, there is just a bit difference in the relation between these LSN's. A differential backup is depending on the previous FULL backup. You can find the LSN of this FULL backup in the backupset of the Differential backup.
The LOG backups are independent of the differential backups. The LOG backups form a sequence starting from the first FULL backup.
So to restore a sequence untill you last LOG backup (T3) you have the following options:
1. Restore F1, D3, T3
2. Restore F1, D2, T2, T3
3. Restore F1, D1, T1, T2, T3
4. Restore F1, T1, T2, T3
The differential backups can shorten the restore process because they 'include' all changes untill that moment and you don't need to restore all previous LOG backups.
** Don't mistake the ‘stupidity of the crowd’ for the ‘wisdom of the group’! **