Here is a list of effects for each elemental type.

2nd is the secondary damage that Lore skill adds to
Effect You can only see the added effect once the
element type is added to an attack

Lore	2nd	Life Dmg	Guts Dmg	CritRate	AccRate	Effect
Fire	Ice	++	-	+	-	Palsy
Ice	Wind	+	++	-	-	Palsy
Thunder	Water	-	+	++	-	Palsy
Water	Earth	-	-	++	+	Slow
Wind	Fire	++	-	-	+	Slow
Earth	Thunder	-	++	-	+	Slow
Heart	n/a	-	++	n/a	-	Addled
Magic	n/a	n/a	-	++	-	Cursed

Note To add an element to a Skill you need to go into
the Customizing screen. Press square and move until you
are next to one of the boxes on an assigned Skill. Press X
and choose one of the elements you know the lore for. The
elemental icon will be next to that attack and the effects
above will be added. Some attacks cannot be modified. See
our Skill charts for details on which can and can't be
enhanced.

Forgot... D Knight deserves Kudos for telling me how to add elements.