If a wizard gains a Tome of Magic he can learn either a spell from his list or a spell from Lesser Magic as per the rule for the Tome. The tome only allows one spell.
If a warrior (a wizard or not) takes the skill Arcane Lore AND obtains a Tome of Magic then he can learn Lesser Magic as per the skill.
The skill requires the Tome.
The Tome in the hands of a wizard does not require the skill, but will only teach one spell.