The Moon-Centered Universe

LRO will spend the rest of its existence in a Moon-centered universe. This diagram illustrates that point of view. (Note that the distances between Earth, Moon, and Sun are not to scale, nor are their sizes.)
At present, Earth is in the lower left (Quadrant 2). The Sun is in the clear wedge at the right. Whenever the Sun is in Gemini (late June through late July), or in Sagittarius (six months later), LRO will receive sunlight throughout its entire lunar orbit, unblocked by the Moon. Earth is continuously visible to the Orbiter when located in Sagittarius (at the left) or Gemini (at the right).
The "ascending/descending" notation refers to LRO's path upward, out of the plane of the diagram (towards the viewer) or downward into the plane of the diagram. Readers with a knowledge of physics or mathematical notation will recognize the vector ("arrow") pointing out of the Moon towards the left. Align your right-hand thumb with the arrow, and then the rest of your fingers will point in the direction of orbital travel. (The "right-hand rule.")
"Eclipse Season" refers to times of the year when LRO will have its view of the Sun blocked by the Moon, ranging from moments (when the Sun is near the clear wedges) to 48 minutes (when the Sun is at the top or bottom of the diagram).
I think the diagram may be in error by using the term "lunar solstice." I think it should be "lunar equinox" (when the Sun is over the Moon's equator, as happens twice a year).
Occasionally, Earth will block all or part of the Sun as seen from LRO. Those events are what we on Earth see as lunar eclipses, when the Moon passes through Earth's shadow.
We've got a few of those coming up this year: July 7, August 6, and December 31. The first two are called "penumbral" eclipses because Earth will not completely block the Sun as seen from anywhere on the Moon. The latter event will be a "partial" eclipse because the Sun will be completely blocked, but only as seen from a part of the Moon (in this case, a relatively small area near the south pole).
Next year will have another partial (June 26, when the northern half of the Moon sees Earth completely cover the Sun) and a "total eclipse," when an observer anywhere on the lunar surface would see the entire Sun blocked for a time. That one is on December 21, lasting 83 minutes. Our power and thermal specialists designed LRO to withstand those conditions, but we will also take special steps to protect the spacecraft during that extended period of darkness, which will last longer than our usual worst-case 48 minutes (twice a month) caused by orbiting over the Moon's midnight longitude.
Note that June and December are when LRO's view of the Sun is perpetually unobstructed by the Moon. That means the shadows caused by Earth will not be extended in duration by LRO then having to pass into the Moon's shadow.
I believe this arrangement was intentionally made by our selection of launch date and lunar intercept point.