We didn't have Honor Roll in elementary school. We do in middle and high school. You have to have all As and Bs (for the academic classes) and Ss and Os (for the specials classes like PE and Art). That gets you Honor Roll. If you make straight As and Os, you get Distinguished Honor Roll. Same for HS, except there are no Ss and Os, just A - F. So many kids make Honor Roll that it's a "whatever" for us. And there are no awards ceremonies. They just bring home a certificate (I don't even know where they all are - in some pile of papers somewhere probably).
If I were you, I'd send the teacher an email asking your very valid question. "I'm curious as to what the criteria are for making Honor Roll. Could you please clarify it for me?" And if it turns out your daughter DID make honor roll using their standards, bring it to the teacher's attention that she missed out on getting the award. It really could have been a mistake, but you won't know unless you ask. And if it wasn't, you'll have something concrete to tell your daughter.
Also, your daughter should start to learn that success in school isn't necessarily the grades and awards, but what she actually learns and accomplishes. She should be proud internally of what she accomplished without some award telling her so. She doesn't need other people telling her "good job". *She* needs to be able to say "I worked really hard and I did a good job." It's a tough lesson for 4th graders and she's young still, but this would be a good place to start.