A lunar eclipse occurs whenever the Moon passes through some portion of the Earth's shadow. This can occur only when the Sun, Earth, and Moon are aligned exactly, or very closely so, with the Earth in the middle. Hence, the Moon is always full during a lunar eclipse.
Therefore when the dark side of the earth faces the moon it is not necessarily an eclipse; rather the 'dark side' is in night, and of course at night we see the moon for most of the month, so it is just a moonlit night.