In terms of the difference, I see "ignorance" as lack of knowledge regarding penetration of the 4NT. I see "delusion" as a temporary condition, the opposite of "vipassana" (seeing things as they really are).
I can't guarantee that's spot on, but that's how I understand them.
"Do not force others, including children, by any means whatsoever, to adopt your views, whether by authority, threat, money, propaganda, or even education." - Ven. Thich Nhat Hanh
"The uprooting of identity is seen by the noble ones as pleasurable; but this contradicts what the whole world sees." (Snp 3.12)
"To argue with a person who has renounced the use of reason is like administering medicine to the dead" - Thomas Paine