Written Expression

The "iffy" part of an "if-then" statement.
Comment: "Antecedent" and "consequent", as technical terms, refer only to parts of a conditional statement. Thus there is neither consequent nor antecedent in statements of the form "A or B", and in particular, A is not the antecedent in such a statement.
Not every statement following the word "if" is the antecedent of a conditional. For example, statements of the form "A only if B" translate into the conditional "If A then B", where you can see that actually B represents the consequent statement, not the antecedent.