  Using time- and angle-resolved photoemission spectroscopy with selective
near- and mid-infrared photon excitations, we investigate the femtosecond
dynamics of the charge density wave (CDW) phase in 1$T$-TiSe$_2$, as well as
the dynamics of CDW fluctuations at 240 K. In the CDW phase, we observe the
coherent oscillation of the CDW amplitude mode. At 240 K, we single out an
ultrafast component in the recovery of the CDW correlations, which we explain
as the manifestation of electron-hole correlations. Our momentum-resolved study
of femtosecond electron dynamics supports a mechanism for the CDW phase
resulting from the cooperation between the interband Coulomb interaction, the
mechanism of excitonic insulator phase formation, and electron-phonon coupling.
