The concept of loneliness applies only to the ego/false self.
The concept of aloneness can apply to the manifested physicality
(the person) in this world.
At very high levels of awareness both loneliness and aloneness
are an impossibility - only the Self, the True Self, is and
that is it.

Lonely = feeling cut off, isolated
Alone   = nobody else consciously detected around

What you consider to be as "you" is always in the presence of the Self,
the True Self, the highest level of God, so absolute loneliness or
aloneness are impossible.
Only the feeling of loneliness or aloneness is possible.
In the case of aloneness, this feeling of aloneness can be
harmonious with the Divine - it may be what the doctor ordered.
In the case of loneliness the feeling of loneliness can only
be experienced by the ego/false self, and it is not harmonious
with the Divine. The ego/false self can feel lonely, because
it can pretend/believe that Love and God don't exist; loneliness
is basically a pretended absence of Love/God, which is in reality
impossible. The absence of Love/God can be experienced by
the ego due to its rejection of Love/God, whether the rejection
is intentionally direct, or as a consequence of other
disharmonious actions/attitudes by the ego/false self.

If loneliness is experienced, it best be rejected/ignored/
surrendered to God, as an emotional drama of the ego;
Acknowledging God and praying to God for help, illumination,
and protection are vital, as well.
Using Neuro-Emotional Technique (NET) to reveal and help
resolve issues blocking Love/God can dramatically assist in
dissolving/transcending loneliness.

Note: under some circumstances, aloneness can be extremely beneficial,
much more than being surrounded by friends and acquaintances.
The spiritual path to enlightenment, to the True Self, is an "inward"
path, and not something "out there". While enlightenment of itself
is not dependent on the lack or presence of people,
sometimes simplifying one's life and minimizing clutter can be of immense
benefit. For a serious spiritual devotee, being in the presence of
supportive, enlightenment-encouraging people can be very beneficial,
but people not interested and not supportive of spirituality can be
of detriment.